Medium-term results of anterior decompression and fusion with nano-hydroxyapatite/polyamide 66 cage in patients with thoracolumbar burst fractures

LIN Shu; YANG Xi; SONG Yue-ming; LIU Li-min; ZENG Jian-cheng; KONG Qing-quan; LI Tao; LIU Hao; GONG Quan; TU Chong-qi; PEI Fu-xing

doi:10.3969/j.issn.2095-252X.2014.01.005

Abstract：Objective To observe the medium-term results of anterior decompression and fusion with nano-hydroxyapatite/polyamide 66 ( n-HA/PA66 ) cage in patients with thoracolumbar burst fractures.Methods The data of 46 patients with thoracolumbar burst fractures who underwent anterior decompression and fusion with n-HA/PA66 cage in our department from January 2008 to November 2009 were retrospectively studied. There were 33 males and 13 females, whose mean age was 54.5 years old. The preoperative and postoperative imaging data of the thoracolumbar spine were collected, including the anteroposterior and lateral X-ray iflms and 3D-CT scans. The clinical data such as the neurological function were classiifed by the Frankel system. The height and sagittal kyphosis of fused segments were measured based on the lateral X-ray iflms, and the fusion status was assessed based on the 3D-CT scans.Results In this study, the patients were followed up for 50 months on average ( 42-64 months ). In the latest follow-up, the fusion rate was 97.8%. The mean height of the fractured vertebral body preoperatively, on 1 and 24 weeks post-operatively and the latest follow-up was 94.3 mm, 108.0 mm, 106.9 mm and 106.2 mm, and the mean kyphosis angle was 18.2°, 5.7°, 6.0° and 6.3°. Both the height and sagittal kyphosis of fused segments were signiifcantly improved on 1 week after the operation compared with that preoperatively (P<0.001 ). However, no statistically signiifcant differences were found in the height or sagittal kyphosis of fused segments on 1 and 24 weeks post-operatively and in the latest follow-up (P>0.05 ). An average of 1.7 mm of cage subsidence was found in the latest follow-up. The preoperativeneurological function was classiifed, including 3 cases of grade A, 6 cases of grade B, 16 cases of grade C, 19 cases of grade D and 2 cases of grade E, and in the latest follow-up there were 1 case of grade A, 2 cases of grade B, 3 cases of grade C, 14 cases of grade D and 26 cases of grade E. According to the Frankel system, the neurological function was improved to different degrees in the latest follow-up when compared with that preoperatively.Conclusions The n-HA/PA66 cage is a proper cage device which can effectively regain and maintain the physical height and sagittal kyphosis of fused segments, promote the osseous fusion and avoid the interference in the postoperative radiographic assessment of surgical segments. The medium-term results of anterior decompression and fusion with n-HA/PA66 cage were satisfactory in the patients with thoracolumbar burst fractures.